The level of Flaming Gorge Reservoir will drop by 9 feet under a plan announced Tuesday by the U.S. Bureau of Reclamation in yet another emergency move to keep power generation possible 450 miles downstream at the Glen Canyon Dam.
With Lake Powell at historic low levels and further declines forecasted, the lake’s volume is expected to fall to a critical threshold below which water cannot pass through the dam’s turbines without wrecking them.
To forestall that possibility, the bureau plans to inject nearly 1 million acre-feet of water into Powell through a combination of holding back releases into the Colorado River from Glen Canyon Dam and releasing 500,000 acre-feet from Flaming Gorge.
“This should add about 16 feet of elevation,” according to the bureau’s Upper Colorado Regional Director Wayne Pullan.
“We made releases last summer from Flaming Gorge and Blue Mesa reservoirs,” he told reporters on Tuesday. “Now, given the extraordinary circumstances, our release from Flaming Gorge is designed to substantively benefit the continued operation at Lake Powell while having a manageable effect on Flaming Gorge.”
These measures come on top of emergency releases last year from Flaming Gorge and two other upstream reservoirs, totaling 161,000 acre-feet.
Inflows into Lake Powell are expected to be less than two-thirds of average thanks to ever-shrinking snowpacks on the Colorado Plateau in the face of climate change that has driven up temperatures and reduced precipitation.
At 3,522 feet above sea level, Lake Powell is already 45 feet lower than it was at this time last year and a mere 32 feet above “minimum power pool.” Vast stretches of sediments, deposited by the Colorado and San Juan rivers over the past 60 years since the lake began filling, are now exposed with new river channels being cut through them.
(Rick Egan | The Salt Lake Tribune) The Glen Canyon Dam, on the Colorado River in northern AZ, on Tuesday, Aug. 3, 2021.
Even with the latest measures, Lake Powell is still expected to fall to 3,501 feet above sea level.
Flaming Gorge, which is 78% full, will begin increasing releases soon with a total of 81,000 acre-feet of additional water sent down the Green River in May. Additional supplemental releases will be made in varying levels each month to achieve a total of 500,000 acre-feet by the end of April 2023, the bureau said.
The resulting declines in Flaming Gorge’s level are expected to cause difficulties for recreational boating and fishing at the popular destination on the Wyoming-Utah state line. Meanwhile, launching boats at Powell, at 23% capacity, has become nearly impossible with most ramps high and dry.
Critics contend the time has come for the Bureau of Reclamation to consider draining Powell, which would allow Glen Canyon to reemerge since the once-mighty reservoir’s demise appears inevitable.
Holding water in Powell also means less water reaching Lake Mead, which is itself at historic lows that could imperil power generation at Hoover Dam. This step marks the first time Glen Canyon Dam’s annual operations, established to carefully balance the water available to the Colorado’s Upper and Lower basins, have been changed.
“Today’s decision reflects the truly unprecedented challenges facing the Colorado River Basin and will provide operational certainty for the next year,” said Tanya Trujillo, the assistant Interior secretary for water and science. “Everyone who relies on the Colorado River must continue to work together to reduce uses and think of additional proactive measures we can take in the months and years ahead to rebuild our reservoirs.”
Besides ensuring power generation for at least another year, Tuesday’s move will also protect water supplies for Page, Ariz. and the LeChee Chapter of the Navajo Nation.
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